Blackberry lily (Iris domestica) is a popular garden plant from Asia that has escaped cultivation in North America. It is now widespread in eastern and central United States but scattered and still uncommon. It has been recorded only twice in Minnesota: once, date unknown but prior to 1991, in Waseca, where it was planted and escaped cultivation; and once on 8/8/2014 in Baker Park Reserve in Hennepin County.
The common name of this plant is a misnomer. It is an iris, family Iridaceae, not a lily, family Liliaceae. It gets its name from the lily-like appearance of the flowers and the blackberry-like appearance of the seed clusters. It blooms from June to July and is typically found on hillsides, pastures, woodland openings, thickets, roadsides, old fields, old homesteads, and disturbed areas. The flowers bloom from dawn to dusk and last only a single day.
At different times in its development, blackberry lily is similar in appearance to some of our native lilies and irises. It is distinguished by a combination of the following characteristics: sword-like basal leaves; alternate, overlapping stem leaves; flowers held erect or horizontal, not hanging downward; sepals and petals widely spreading, not curved backward; and clusters of black seeds that look similar to blackberries.